U.S. Pat. No. 4,521,192 discloses an oral implant allowing for the immediate installation of an artificial tooth support structure in a jawbone portion which has become oversized due to a failed prior blade implant or an enlarged tooth socket. The implant includes one or more posts upon which the artificial tooth is mounted, as well as a support structure whose lateral dimensions is sufficient to permit it to be wedged in the oversized opening. The support structure is perforated, and bone fragments or calcium phosphate are filled in the support structure.
U.S. Pat. No. 5,383,935 discloses a prosthetic implant for implantation into skeletal bone comprising an implantable base member having an internal housing surrounded partially by a porous wall, an anode secured in the internal housing in electrical contact with the porous wall, and a porous means placed in the internal housing for retaining a biocompatible electrolyte. When implanted into bone structure, the prosthetic implant generates sufficient current flow which results in in-vivo formation of calcium phosphate minerals between the implant and the surrounding bone, thereby, resulting in improved fixation and stability of the implant.
Heretofore bone graft such as calcium phosphate, calcium sulfate and bioactive glass, etc. are filled in grooves and cavities of the dental implants in the form of particles in addition to bone fragments taken from the patient during operation. Disadvantages of using particles or bone fragments in filling the dental implants include the following among others:                Low strength, so that the wall thickness of the dental implant is not able to be further reduced.        Mechanically unstable, wherein movement or micro-movement of the particles or bone fragments will induce fibrous tissue not bone tissue to grow in the filled dental implants.        Leakage of the particles or bone fragments from the through-thickness holes of the filled dental implants, so that the diameter of the through-thickness holes is restricted, which adversely affects the in-growth of bone tissue.        